Network unreachable, Host unreachable, Icmp redirect – Allied Telesis Rapier Series User Manual
Page 15: Commands, Disable ip icmpreply

Patch 86253-04 For Rapier Series Switches
15
Patch 86253-04 for Software Release 2.5.3
C613-10382-00 REV C
The ICMP messages that are able to be enabled or disabled are:
■
Network unreachable (RFC792 Type 3 Code 0)
■
Host unreachable (RFC792 Type 3 Code 1)
■
ICMP redirect messages (RFC792 Type 5 Code 0, 1, 2, 3)
Network Unreachabl
e
This message indicates that the switch does not know how to reach the
destination network.
Host Unreachabl
e
This message indicates that the switch does not know how to reach the host.
ICMP Redirect
This message is sent to a local host to tell it that its
target is located on the same
LAN (no routing is required) or when it detects a host using a non-optimal route
(usually because a link has failed or changed its status)
on a directly connected
router to advise of a better route to a particular destination.
For more information on ICMP, see the IP Chapter in your switch’s Software
Reference manual.
Commands
This enhancement introduces three new commands:
■
DISABLE IP ICMPREPLY
■
ENABLE IP ICMPREPLY
■
SHOW IP ICMPREPLY
DISABLE IP ICMPREPLY
Syntax
DISABLE IP
ICMPREPLY[={ALL|NETUNREACH|HOSTUNREACH|REDIRECT}]
Description
This command disables ICMP reply messages.
If ALL is specified, all configurable ICMP message replies are disabled. If
NETUNREACH is specified, all network unreachable message replies are
disabled (RFC792 Type 3 Code 0). If HOSTUNREACH is specified, all host
unreachable message replies are disabled (RFC792 Type 3 Code 1). If
REDIRECT is specified, all ICMP redirect message replies are disabled (RFC792
Type 5 Code 0, 1, 2, 3).
Example
To disable all configurable ICMP messages, use the command:
DISABLE IP ICMPREPLY=ALL